Basic knowledge of transformer pump oil pump products

Transformer (air pressure variable) tester oil pump-is a fully sealed structure, built-in submersible oil operation three-phase asynchronous motor straight shaft drive a centrifugal or axial flow vane pump, dedicated to transport insulating oil for transformer tester Media fluid machinery. Transformer DC resistance tester is a new generation product of transformer DC resistance measurement, which is optimized for measuring the DC resistance of three-phase windings of large-capacity transformers. The transformer DC resistance tester can simultaneously test the DC resistance of the three-phase windings of the transformer. The centrifugal transformer tester oil pump is suitable for the transformer tester strong oil air cooler; the axial flow transformer tester oil pump (low lift, large flow) is suitable for the transformer tester chip radiator. Divided by drive motor structure: currently used in domestic supporting

â‘  Ordinary transformer tester oil pump for submersible oil design of traditional three-phase asynchronous motor;

②Axial air gap (disc motor) motor-driven disc transformer tester oil pump. The transformer capacity tester can automatically adjust the output voltage and current, and can adapt to the test of transformers with different capacities, and has a wide range of applications. When measuring transformer capacity and transformer short-circuit loss, there is no need for external three-phase test power supply, voltage regulator, current booster and other auxiliary equipment, which simplifies wiring and greatly improves work efficiency; the accuracy of capacity test results reaches 100%. Waveform display, vector analysis and harmonic test functions are newly added to make the device function no less than a high-level power analyzer. Transformer resistance tester is an indispensable test item after handover, overhaul and change of tap changer. Under normal circumstances, using traditional methods (bridge method and voltage drop method) to measure the DC resistance of transformer windings and high-power inductive devices is a time-consuming and labor-intensive task. In order to change this situation, shorten the measurement time and reduce the workload of testers. The difference between the two structures is mainly the drive motor, the use function and the installation form are exactly the same. However, due to the unique axial magnetic pulling force of the disc pump, the bearings that are worn (a basic type of component failure) must be replaced in time to prevent the rotor from falling and causing strong mechanical friction. At present, it is still widely used abroad that the conventional three-phase asynchronous motor is specially designed for the ordinary type transformer tester oil pump. Head and flow are irreplaceable for each specific type of pump, because only one point on the characteristic curve of each type of pump is highly efficient. The point where the pump works is called the rated operating point. When the pump works in this area, not only high efficiency, but also low noise (dB), reasonable power consumption, smooth operation, and no harmful eddy current ) Impact and cavitation damage can maintain long-term reliable operation. The selection of the above-mentioned operating point is determined by the resistance characteristic curve of the pipe network system of the main transformer cooling oil circuit. Different types of coolers and main transformer oil circuit circulation structure have different pipe network curves. The intersection of the resistance characteristic curve of the pipe network system and the oil pump working characteristic curve of the transformer tester is the rated operating point of the oil pump. Therefore, as far as the replacement of the oil pump of the transformer tester is concerned, random replacement of different hydraulic parameters or reducing hydraulic parameters is not desirable. It is related to the safe operation of the main transformer and the rated heat exchange capacity of the cooler. At present, the domestic power grids and bureaus have changed the original 1450 rpm (4-pole motor) oil pump to 1000 rpm (6-pole motor) in order to improve the operating life of the oil pump bearing of the transformer tester according to the requirements of the Company. The following oil pump. The oil pump of the transformer tester of 1000 rpm (6 pole motor) must reach the flow rate and head of the (4 pole motor) oil pump, which must be solved by increasing the diameter of the impeller. As the diameter of the rotating machine increases, the operation is stable (explained: stable and stable; no change), and the 6-pole drive motor has a larger diameter than the 4-pole motor. In this way, in the replacement process, some old cooler installation dimensions (such as 4B240-16 / 3V oil pumps) are difficult to achieve. Changchun Nuosen Motor Co., Ltd. adopts a two-stage pump structure to solve the replacement problem of such oil pumps, but the manufacturing cost increases. In fact, at present, domestic and foreign pump products are developing towards high speed and direction. Appropriate high-speed transformer tester oil pump not only has high efficiency but also small volume and good running stability. Of course, low speed can improve the running life of the bearing. However, as the diameter of the impeller increases, the balance problem will become more prominent, especially as the consistency of the blade casting and twist angle of the vane pump is inevitable in the process, these are the key factors that affect the operational stability. If it is not good, it will reduce the running life of the bearing. At present, many domestic units are equipped with a large number of oil pumps for disk transformer testers driven by axial air gap (disk motors) motors (such oil pumps are suitable for low speeds below 1000 rpm). Such problems will be more prominent. Because the axial magnetic pulling force of the disc motor is very strong, (it is this kind of rotating axial magnetic pulling force that is used for magnetic-electric coupling to rotate the rotor to complete the energy conversion.) The axial magnetic pulling force will cause the bearing to wear The measuring gap is directly converted into a reduction in the enlargement of the air gap between the stator and rotor, until the strong friction between the stator and rotor iron and iron. (The disc motor is very suitable for making a brake motor: the brake pads are installed between the stator and the rotor, the brake is energized, and the power is free to rotate.) Therefore, the common type of conventional three-phase asynchronous motor designed for the conventional transformer tester oil pump is widely used abroad. . Only we are still widely using the disc motor transformer tester oil pump as a new product. If the strict monitoring of the bearings is ignored during operation, the probability of accidents will increase with the accumulation of the operating time of the oil pump of this structure. The manual of this kind of disk transformer tester oil pump produced by Japan (GOOGLEPRoduce) explains the maintenance of the bearing in a lot of space, and the formula is as follows: Lh = (106 / 60N) (C / Prfw) 3a1a2a3Lh: calculated life (hr); N: speed (rot / min); C: rated load (kg); Pr: equivalent bearing load (kg); fw: load factor; a1: reliability factor; a2: lubrication factor; a3: material factor ; Even if the above formulas give recommended values ​​for various parameters, it is difficult to accurately calculate the operating life of the oil pump due to factors such as the choice of materials, the environment, the manufacturing process, and so on. In my opinion, the actual responsibility is given to the user. China's traditional 1450 rpm (4-pole motor) oil pump, and even 2860 rpm (2-pole motor) transformer tester oil pumps have some varieties that have very good operating performance, and some products have been operating for more than 20 years and are still running well. . Therefore, the key is good, professional manufacturing quality and operation and maintenance. It is not possible to deny it all because of some quality problems. In fact, the maintenance experience and opinions of some operating units are also worthy of respect. The 6B4 and 6B5 types of ordinary type transformer tester oil pumps with a low speed of less than 1000 rpm (6-pole motor) have been put into operation, but due to the late investment time and insufficient publicity, people think that only 6PB disc pumps are low-speed pumps . In fact, the hydraulic parameters, installation size, and main performance can be replaced between the two.